1 Linux kernel release 2.4.xx
3 These are the release notes for Linux version 2.4. Read them carefully,
4 as they tell you what this is all about, explain how to install the
5 kernel, and what to do if something goes wrong.
7 WHAT IS LINUX?
9 Linux is a Unix clone written from scratch by Linus Torvalds with
10 assistance from a loosely-knit team of hackers across the Net.
11 It aims towards POSIX compliance.
13 It has all the features you would expect in a modern fully-fledged
14 Unix, including true multitasking, virtual memory, shared libraries,
15 demand loading, shared copy-on-write executables, proper memory
16 management and TCP/IP networking.
18 It is distributed under the GNU General Public License - see the
19 accompanying COPYING file for more details.
21 ON WHAT HARDWARE DOES IT RUN?
23 Linux was first developed for 386/486-based PCs. These days it also
24 runs on ARMs, DEC Alphas, SUN Sparcs, M68000 machines (like Atari and
25 Amiga), MIPS and PowerPC, and others.
29 - There is a lot of documentation available both in electronic form on
30 the Internet and in books, both Linux-specific and pertaining to
31 general UNIX questions. I'd recommend looking into the documentation
32 subdirectories on any Linux FTP site for the LDP (Linux Documentation
33 Project) books. This README is not meant to be documentation on the
34 system: there are much better sources available.
36 - There are various README files in the Documentation/ subdirectory:
37 these typically contain kernel-specific installation notes for some
38 drivers for example. See ./Documentation/00-INDEX for a list of what
39 is contained in each file. Please read the Changes file, as it
40 contains information about the problems, which may result by upgrading
41 your kernel.
43 INSTALLING the kernel:
45 - If you install the full sources, put the kernel tarball in a
46 directory where you have permissions (eg. your home directory) and
47 unpack it:
49 gzip -cd linux-2.4.XX.tar.gz | tar xvf -
51 Replace "XX" with the version number of the latest kernel.
53 Do NOT use the /usr/src/linux area! This area has a (usually
54 incomplete) set of kernel headers that are used by the library header
55 files. They should match the library, and not get messed up by
56 whatever the kernel-du-jour happens to be.
58 - You can also upgrade between 2.4.xx releases by patching. Patches are
59 distributed in the traditional gzip and the new bzip2 format. To
60 install by patching, get all the newer patch files, enter the
61 directory in which you unpacked the kernel source and execute:
63 gzip -cd patchXX.gz | patch -p0
66 bzip2 -dc patchXX.bz2 | patch -p0
68 (repeat xx for all versions bigger than the version of your current
69 source tree, _in_order_) and you should be ok. You may want to remove
70 the backup files (xxx~ or xxx.orig), and make sure that there are no
71 failed patches (xxx# or xxx.rej). If there are, either you or me has
72 made a mistake.
74 Alternatively, the script patch-kernel can be used to automate this
75 process. It determines the current kernel version and applies any
76 patches found.
78 linux/scripts/patch-kernel linux
80 The first argument in the command above is the location of the
81 kernel source. Patches are applied from the current directory, but
82 an alternative directory can be specified as the second argument.
84 - Make sure you have no stale .o files and dependencies lying around:
86 cd linux
87 make mrproper
89 You should now have the sources correctly installed.
91 SOFTWARE REQUIREMENTS
93 Compiling and running the 2.4.xx kernels requires up-to-date
94 versions of various software packages. Consult
95 ./Documentation/Changes for the minimum version numbers required
96 and how to get updates for these packages. Beware that using
97 excessively old versions of these packages can cause indirect
98 errors that are very difficult to track down, so don't assume that
99 you can just update packages when obvious problems arise during
100 build or operation.
102 CONFIGURING the kernel:
104 - Do a "make config" to configure the basic kernel. "make config" needs
105 bash to work: it will search for bash in $BASH, /bin/bash and /bin/sh
106 (in that order), so one of those must be correct for it to work.
108 Do not skip this step even if you are only upgrading one minor
109 version. New configuration options are added in each release, and
110 odd problems will turn up if the configuration files are not set up
111 as expected. If you want to carry your existing configuration to a
112 new version with minimal work, use "make oldconfig", which will
113 only ask you for the answers to new questions.
115 - Alternate configuration commands are:
116 "make menuconfig" Text based color menus, radiolists & dialogs.
117 "make xconfig" X windows based configuration tool.
118 "make oldconfig" Default all questions based on the contents of
119 your existing ./.config file.
121 NOTES on "make config":
122 - having unnecessary drivers will make the kernel bigger, and can
123 under some circumstances lead to problems: probing for a
124 nonexistent controller card may confuse your other controllers
125 - compiling the kernel with "Processor type" set higher than 386
126 will result in a kernel that does NOT work on a 386. The
127 kernel will detect this on bootup, and give up.
128 - A kernel with math-emulation compiled in will still use the
129 coprocessor if one is present: the math emulation will just
130 never get used in that case. The kernel will be slightly larger,
131 but will work on different machines regardless of whether they
132 have a math coprocessor or not.
133 - the "kernel hacking" configuration details usually result in a
134 bigger or slower kernel (or both), and can even make the kernel
135 less stable by configuring some routines to actively try to
136 break bad code to find kernel problems (kmalloc()). Thus you
137 should probably answer 'n' to the questions for
138 "development", "experimental", or "debugging" features.
140 - Check the top Makefile for further site-dependent configuration
141 (default SVGA mode etc).
143 - Finally, do a "make dep" to set up all the dependencies correctly.
145 COMPILING the kernel:
147 - Make sure you have gcc-2.91.66 (egcs-1.1.2) available. gcc 2.95.2 may
148 also work but is not as safe, and *gcc 22.214.171.124 is no longer supported*.
149 Also remember to upgrade your binutils package (for as/ld/nm and company)
150 if necessary. For more information, refer to ./Documentation/Changes.
152 Please note that you can still run a.out user programs with this
155 - Do a "make bzImage" to create a compressed kernel image. If you want
156 to make a boot disk (without root filesystem or LILO), insert a floppy
157 in your A: drive, and do a "make bzdisk". It is also possible to do
158 "make install" if you have lilo installed to suit the kernel makefiles,
159 but you may want to check your particular lilo setup first.
161 To do the actual install you have to be root, but none of the normal
162 build should require that. Don't take the name of root in vain.
164 - In the unlikely event that your system cannot boot bzImage kernels you
165 can still compile your kernel as zImage. However, since zImage support
166 will be removed at some point in the future in favor of bzImage we
167 encourage people having problems with booting bzImage kernels to report
168 these, with detailed hardware configuration information, to the
169 linux-kernel mailing list and to H. Peter Anvin <email@example.com>.
171 - If you configured any of the parts of the kernel as `modules', you
172 will have to do "make modules" followed by "make modules_install".
173 Read Documentation/modules.txt for more information. For example,
174 an explanation of how to use the modules is included there.
176 - Keep a backup kernel handy in case something goes wrong. This is
177 especially true for the development releases, since each new release
178 contains new code which has not been debugged. Make sure you keep a
179 backup of the modules corresponding to that kernel, as well. If you
180 are installing a new kernel with the same version number as your
181 working kernel, make a backup of your modules directory before you
182 do a "make modules_install".
184 - In order to boot your new kernel, you'll need to copy the kernel
185 image (found in .../linux/arch/i386/boot/bzImage after compilation)
186 to the place where your regular bootable kernel is found.
188 For some, this is on a floppy disk, in which case you can copy the
189 kernel bzImage file to /dev/fd0 to make a bootable floppy. Please note
190 that you can not boot a kernel by directly dumping it to a 720k
191 double-density 3.5" floppy. In this case, it is highly recommended
192 that you install LILO on your double-density boot floppy or switch to
193 high-density floppies.
195 If you boot Linux from the hard drive, chances are you use LILO which
196 uses the kernel image as specified in the file /etc/lilo.conf. The
197 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
198 /boot/bzImage. To use the new kernel, save a copy of the old image
199 and copy the new image over the old one. Then, you MUST RERUN LILO
200 to update the loading map!! If you don't, you won't be able to boot
201 the new kernel image.
203 Reinstalling LILO is usually a matter of running /sbin/lilo.
204 You may wish to edit /etc/lilo.conf to specify an entry for your
205 old kernel image (say, /vmlinux.old) in case the new one does not
206 work. See the LILO docs for more information.
208 After reinstalling LILO, you should be all set. Shutdown the system,
209 reboot, and enjoy!
211 If you ever need to change the default root device, video mode,
212 ramdisk size, etc. in the kernel image, use the 'rdev' program (or
213 alternatively the LILO boot options when appropriate). No need to
214 recompile the kernel to change these parameters.
216 - Reboot with the new kernel and enjoy.
218 IF SOMETHING GOES WRONG:
220 - If you have problems that seem to be due to kernel bugs, please check
221 the file MAINTAINERS to see if there is a particular person associated
222 with the part of the kernel that you are having trouble with. If there
223 isn't anyone listed there, then the second best thing is to mail
224 them to me (firstname.lastname@example.org), and possibly to any other
225 relevant mailing-list or to the newsgroup. The mailing-lists are
226 useful especially for SCSI and networking problems, as I can't test
227 either of those personally anyway.
229 - In all bug-reports, *please* tell what kernel you are talking about,
230 how to duplicate the problem, and what your setup is (use your common
231 sense). If the problem is new, tell me so, and if the problem is
232 old, please try to tell me when you first noticed it.
234 - If the bug results in a message like
236 unable to handle kernel paging request at address C0000010
237 Oops: 0002
238 EIP: 0010:XXXXXXXX
239 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
240 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
241 ds: xxxx es: xxxx fs: xxxx gs: xxxx
242 Pid: xx, process nr: xx
243 xx xx xx xx xx xx xx xx xx xx
245 or similar kernel debugging information on your screen or in your
246 system log, please duplicate it *exactly*. The dump may look
247 incomprehensible to you, but it does contain information that may
248 help debugging the problem. The text above the dump is also
249 important: it tells something about why the kernel dumped code (in
250 the above example it's due to a bad kernel pointer). More information
251 on making sense of the dump is in Documentation/oops-tracing.txt
253 - You can use the "ksymoops" program to make sense of the dump. This
254 utility can be downloaded from
256 Alternately you can do the dump lookup by hand:
258 - In debugging dumps like the above, it helps enormously if you can
259 look up what the EIP value means. The hex value as such doesn't help
260 me or anybody else very much: it will depend on your particular
261 kernel setup. What you should do is take the hex value from the EIP
262 line (ignore the "0010:"), and look it up in the kernel namelist to
263 see which kernel function contains the offending address.
265 To find out the kernel function name, you'll need to find the system
266 binary associated with the kernel that exhibited the symptom. This is
267 the file 'linux/vmlinux'. To extract the namelist and match it against
268 the EIP from the kernel crash, do:
270 nm vmlinux | sort | less
272 This will give you a list of kernel addresses sorted in ascending
273 order, from which it is simple to find the function that contains the
274 offending address. Note that the address given by the kernel
275 debugging messages will not necessarily match exactly with the
276 function addresses (in fact, that is very unlikely), so you can't
277 just 'grep' the list: the list will, however, give you the starting
278 point of each kernel function, so by looking for the function that
279 has a starting address lower than the one you are searching for but
280 is followed by a function with a higher address you will find the one
281 you want. In fact, it may be a good idea to include a bit of
282 "context" in your problem report, giving a few lines around the
283 interesting one.
285 If you for some reason cannot do the above (you have a pre-compiled
286 kernel image or similar), telling me as much about your setup as
287 possible will help.
289 - Alternately, you can use gdb on a running kernel. (read-only; i.e. you
290 cannot change values or set break points.) To do this, first compile the
291 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
292 clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
294 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
295 You can now use all the usual gdb commands. The command to look up the
296 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
297 with the EIP value.)
299 gdb'ing a non-running kernel currently fails because gdb (wrongly)
300 disregards the starting offset for which the kernel is compiled.
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